I'm going to assume you've got a Puppet module already on GitHub. To save
messing around with bundler on your local machine, I recommend installing
puppet-lint and rspec-puppet as system gems while you're getting this all
set up.

puppet-lint

Next up, we'll also get some automatic lint testing of your manifests going to
ensure you're writing manifests that comply with the Puppet Labs style guide.
This is simply a matter adding the following line near the top of your
Rakefile

1require'puppet-lint/tasks/puppet-lint'

You can now run rake lint to run puppet-lint over your manifests.

Travis CI

Travis CI is a wonderful free continuous integration
service that integrates with GitHub, running whatever
tests you want against your code every time you push.

To get Travis CI automatically testing your module you need to add a couple of
files to the root directory of your module.

First, create a Gemfile which tells bundler which ruby gems your tests need in
order to run. If your module needs any additional gems, just add them to the
bottom of this file.